(Zinnia elegans) Zinnia is an annual member of the aster family and comes in an incredible rainbow of colors. Native to Mexico and Central America, it was grown by the ancient Aztecs and later brought to Europe in the 1700s. Zinnia prefers full sun and needs rich, well-drained soil. Space plants 9-12 inches apart. Keep deadheaded to encourage continued blooming. Sow seeds indoors four weeks before last frost, or direct seed after the threat of frost has passed. Seeds germinate in 5-7 days. Ideal germination temperature 75-80 F.